To conduct the study, researchers from Queen Mary, University of London and the University of Oxford looked at the immune system development of newborn babies and their vitamin D levels.

Blood samples of from the newborns’ umbilical cords – 50 who were born in May and 50 who were born in November, between 2009 and 2010 in London – showed May babies had 20 per cent lower levels of vitamin D than November babies had.

The study also found that those born in May has double the levels of potentially harmful autoreactive T-cells, which can attack the body’s own cells and trigger autoimmune diseases.

"By showing that month of birth has a measurable impact on in utero immune system development, this study provides a potential biological explanation for the widely observed ‘month of birth’ effect in MS,” study co-author Dr. Sreeram Ramagopalan said in a statement. “Higher levels of autoreactive T-cells, which have the ability to turn on the body, could explain why babies born in May are at a higher risk of developing MS.”

Ramagopalan said the study points to a need to study the effect of vitamin D supplements on pregnant women.

Canada has one of the highest rates of MS in the world – with three Canadians diagnosed with the disease each day. Women are three times more likely to be diagnosed.

MS affects the brain and spinal cord and symptoms include loss of balance, impaired speech, extreme fatigue, double vision and paralysis. It is most often diagnosed in young adults, aged 15 to 40, but it could also affect young children.

Scientists have long-theorized that a lack of sun in countries such as Canada and the United Kingdom could be behind the high MS rates as countries closest to the equator have the lowest rates of the disease.

“There’s interplay here between genetics, the environment, perhaps lack of vitamin D and how vitamin D influences the development in the uterus,” says CTV’s Medical Expert Dr. Marla Shapiro.

Shapiro told CTV’s Canada AM on Tuesday that an individual’s birth month has also been linked to other immune conditions such as Type 1 diabetes and rheumatoid arthritis.

“That would be the next part of the study, that in fact we talk about women taking folic acid during pregnancy and prenatally, should we be pumping up vitamin D as well.”